Hello

I want to model the O2 consumption on tissue surface as Michaelis-Menten equation, which states:

R=Vm*Ci/(K+Ci)

where Vm and K are constant and Ci is O2 concentration at the wall. In UDF (DEFINE_SR_RATE) Ci is defined by the molar concentration, therefore I have to convert it by multiplying the mass fraction of O2 by density and divide it by the molar weight, am I right?. I think the density must be defined at the centre not the face and in surface reaction is defined at the face, so how can I get the density at the cell centre? please help!!.

Thanks

DEFINE_SR_RATE(user_rate,f,t,r,mole_weight,species _mf,rate) {

dcell = C_R(F_C0(f,t),t->t0); *rate = /*kmol/m2-s */ }

Hi Saghir,

Thanks, but can please explain more?. I tried to do like this:

Thread *t0=t->t0;

cell_t c0=F_C0(f,t);

c1=C_R(c0,t0)*s1/mw1;

but i got this msg "structure reference not implemented".

Regards

you must write directly

reel dcell; dcell = C_R(F_C0(f,t),t->t0); or

Thread *t0; cell_t c0; c0 = F_C0(f,t); t0 = THREAD_T0(t); reel dcell; dcell = C_R(c0,t0);

hi, can u explain about ur problem.

Thanks Saghir,

i guess my problem is in the compiler, I will try to install a new one and try agin. many thanks,

Hi Suribabu, my problem is mentioned in the first post here by Jon.

Regards,